1. Technical Field of the Invention
The present invention relates in general to Ethernet Operations, Administration and Management (OAM), and in particular, to the incorporation of new features in the Ethernet OAM protocol.
2. Description of Related Art
Ethernet OAM provides protocols for installing, monitoring and troubleshooting Ethernet metropolitan area networks (MANs) and Ethernet wide area networks (WANs). Several different standards bodies have developed working protocols for Ethernet OAM. For example, the Institute of Electrical and Electronics Engineers (IEEE) has produced the IEEE 802.1ag standard, which defines Connectivity Fault Management (CFM) in enterprise and carrier networks. Similarly, the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) has produced the Y.1731 standard, which defines both fault management and performance monitoring in carrier networks.
The IEEE 802.1ag standard further partitions the network into hierarchical maintenance domains (MDs) and defines roles for maintenance endpoints (MEPs) and maintenance intermediate points (MIPs) within each domain. For example, a customer (higher) level domain includes maintenance endpoints (MEPs) within customer premises equipment and maintenance intermediate points (MIPs) within provider edge switches and core operator switches, while a provider (lower) level domain includes MEPs within provider edge switches and MIPs within core operator switches. Thus, the lower level domain MEPs are nested with the higher level domain MIPs within the provider edge switches.
Currently, the Ethernet OAM Protocol, as described in the IEEE 802.1ag standard and similarly described in the ITU-T Y.1731 standard, includes the following primitives: Fault Detection, Fault Verification and Fault Isolation. Fault Detection is supported using CFM Continuity Check Messages (CCMs), which are “heartbeat” messages issued periodically by maintenance endpoints (MEPs) in the network. CCMs allow MEPs to detect loss of service connectivity amongst themselves, enable MEPs to discover other MEPs within an Ethernet maintenance domain (MD) and enable maintenance intermediate points (MIPs) to discover MEPs.
Fault Verification is supported using CFM Loop-Back messages, which are transmitted by MEPs at the request of an administrator to verify connectivity to a particular maintenance point (MEP or MIP). Fault Isolation is supported using link trace messages, which are transmitted by a MEP at the request of an administrator to track the path (hop-by-hop) to a destination MEP. Link trace allows the transmitting MEP to discover connectivity data about the path.
However, the current standards for Ethernet OAM in IEEE 802.1ag and ITU-T Y.1731 do not provide any tools for service level mirroring of the traffic. Therefore, network administrators often have to address customer complaints regarding specific network problems by deploying employees to the customer site to monitor the traffic under certain conditions and in certain traffic scenarios. Therefore, what is needed is a standardized tool for configuring service level mirroring end to end and on the fly for remote monitoring and debugging.